Irradiation of Cellulosic Pulps: Understanding Its Impact on Cellulose Oxidation

Abstract

Different pulp samples were irradiated by three energy sources: plasma, electron beaming, and γ radiation. The effect of increased exposure to irradiation was studied by multidetector gel permeation chromatography with fluorescence labeling of carbonyl groups to quantify changes of the cellulose. Whereas plasma treatment had no effect, for gamma and electron beam the degradation primarily affects the high molar mass area. Kinetic calculations based on DPw were performed. They show close-to-linear relations with slopes in the same order of magnitude, suggesting that wood-derived pulps degrade slower than pulps from annual plants. The rise in carbonyl group content is linear with increasing dose. In particular, in pulps from annual plants, most detected carbonyl structures originate from the new reducing end groups. Therefore, oxidative modification of cellulose molecules by means of radiation appears to be viable for pulps produced from wood. Here the increase in oxidized functionalities is partially disconnected from chain scission.

Changes in Chemical Composition and Microstructure of Bamboo after Gamma Ray Irradiation

“…In low doses up to 50 KGy, the efficient chain scissions are the main mechanisms that provide a high number of carbonyl groups. This is in good agreement with the water and 1% NaOH extraction results and is consistent with a previous study (Henniges et al 2012). …”

Free radical grafting of gallic acid (GA) on cellulose nanocrystals (CNCS) and evaluation of antioxidant reinforced gellan gum films

“…In literature, it has been investigated that gamma-irradiation exhibits scission of cellulose chains (Henniges et al, 2012). As it is known, cellulose is constituted by linked β(1-4) D-glucose units.…”

Electron Beam Irradiation of Cellulosic Materials—Opportunities and Limitations

“…Mostly, different oxidized functionalities (carbonyls—keto and aldehyde groups also as hydrates, hemiketals and hemiacetals—and carboxyls) tend to originate in addition to newly generated reducing end groups (REGs) formed upon chain scission. Consequently, for modifying cellulose, only mild irradiation can be applied, otherwise the negative impact caused by chain scission will render the irradiated material mechanically too weak [15]. Another aspect of electron beam irradiation refers to the decrease of the amount of I-alpha cellulose [4].…”